1. Field of the Invention
The present invention is directed to steaming pitchers for making hot beverages, and more particularly to temperature monitoring devices for detecting the temperature of fluids heated within steaming pitchers.
2. Description of the Relevant Art
The current practice in the specialty coffee industry is to use food service thermometers with metal probes that clip onto the edge of a steaming pitcher which is used to heat liquids such as milk. The individual heating liquid in the pitcher uses the thermometer to gauge the temperature of the milk as the milk is being steamed or frothed with a steam wand on a machine such as an espresso machine. The milk is then added to fresh brewed espresso to make the desired specialty coffee drink--a cappuccino or caffe latte, for example.
The problems typically encountered when using this type of thermometer are numerous. If the volume level of the milk in the steaming pitcher does not rise above the middle of the thermometer's probe, the temperature indicated on the dial will be inaccurate. When "frothing" milk for a cappuccino, the foam created has a low density, the temperature of which is not accurately measured using a conventional thermometer.
Operators need to periodically adjust the thermometer to assure accurate measure of temperature. Conventional thermometers, because they are directly exposed to the milk, must be kept clean to assure safety in terms of public health. Conventional thermometers are relatively fragile--they need to be replaced fairly often as they break or are found to be inaccurate.
One of the most common mistakes made by individuals who prepare specialty coffee drinks, such as cappuccino, is "scalding" the milk. Scalding is the process by which milk or other liquid is heated above a critical temperature, approximately 175.degree. F. at which point the proteins in the milk are degraded. This not only affects the flavor of the drink produced, but more importantly, poses a threat of burning the consumer of the drink. This occurs very frequently, even when a conventional thermometer is used.
It has now been found that a liquid crystal thermometer (hereinafter "LCT"), properly affixed to a steaming pitcher solves each of the aforementioned problems. Although placing a thermometer on the exterior of a container is not new, the application to a steaming pitcher to solve problems unique to steaming pitchers is. For example, U.S. Pat. No. 5,304,003 to Winninger teaches the use of a LCT that is applied to the exterior surface of a back wall of an aquarium with the graduations facing the interior of the aquarium. Use of clear adhesive to form an airtight attachment of the LCT to the aquarium back wall enables one to view the LCT graduations through the aquarium walls from the front of the aquarium. Winninger's use of a inwardly facing LCT and use of transparent adhesives are not useful with respect to steaming pitchers which are typically made from stainless steel which is a well known opaque material.
U.S. Pat. No. 5,588,747 to Blevins discloses a LCT affixed to the exterior of a measuring cup which is preferably insulated. The thermometer, by design, is not used to detect the temperature of the contents of the cup particularly with respect cups that are insulated. Instead, the substances that will eventually be added to the cup are allowed to flow over the exterior of the cup and the thermometer until the substances reach the desired temperature. The substances are then placed in the cup.
Bleven's use of a LCT on the exterior of the container for measuring temperature of substances allowed to flow over the thermometer will not solve the problems associated with steaming pitchers. It is imperative that the thermometer affixed to the exterior of a steaming pitcher be able to accurately detect the temperature of the steaming pitcher contents while being heated in the pitcher and not before being introduced into the pitcher.
It is thus an object of the invention to provide a thermometer for steaming pitchers that is durable and will withstand substantial cycling between heating, cooling and cleaning cycles. Another object of the invention is to provide a thermometer that will accurately gauge the temperature of the liquid in the steaming pitcher. A further object of the invention is to provide a thermometer that cuts down on the effort needed to clean the temperature sensing device.